Hydrocarbon oil extraction



Patented May 9, 1933 UNITED STATES PATENT OFFICE 5 LAWRENCE M. nrmnnason, or Nansen ATLANTIC anrmme comramr, or rm TION OF PENNSYLVANIA TH, PENNSYLVANIA, ASSIGNOR 'JIO THE LADELPHIA, PENNSYLVANIA, A CORPOBA- mnoomnon on. Ex'rmc'non No Drawing.

The present invention relates to the art of mineral oil refining, and has particular reference to the separation of crude petroleum products into fractions of different chemical compositions while of approximately the same distillation range.

In accordance with my invention, crude petroleum or petroleum products, particularly oils of substantial viscosity, are separatedinto various fractions by means of fractional extraction with ethylene glycol ethers and their acyl derivatives or mixtures there- 'or homologous series of compounds, such for example, as paraflins of the general formula C H olefines of the general formula hydroaromatics and polymethylenes of the same empirical formula, and various other series of compounds of chain and/or .ring structures in which the hydrogen to carbon ratio is less than in the foregoing series. A large number of individual compounds of each series and of differing boiling points are present in petroleum.

he various types of crude petroleum, which are generally classified into three groups, namely, paraffinic base, naphthenic or asphaltic base, and mixed base,'contain the various series of hydrocarbons mentioned heretofore in different proportions. For example, in the parafiin base crude oils, such as those obtained from the oil fields of Pennsyl- Vania, there is a relatively high proportion of hydrocarbons having a chain structure and a high hydrogen to carbon ratio, whereas in the naphthenic or asphaltic base crude oils,

there is a relatively large proportion of by drocarbons having ring structures and a low hydrogen to carbon ratio. Mixed base crude oils, such as are obtained from the Mid-Continent oil fields, contain hydrocarbons in proportions intermediate these two extremes,

As the use of practically all of the petroleum oils is almost entirely physical, the above described chemical nature of those oils Application filed Kay 22, 1931. Serial No. 589,411.

is important in reflecting certain physical characteristics.

The variance in the proportion of the different series of hydrocarbons in parafiinic, naphthenic, and mixed base oils is evidenced by the physical properties of the various oils and particularly by the relationship of the specific gravit to the viscosity of one oil as compared wit another. derived from a Pennsylvania crude and havversal at 100. F., will show a speci c gravity at F. of about 0.878,.whereas in oil of corresponding viscosity produced from a naphthenic crude, such as one from the Gulf Coast area, will show a specific gravity of about 0.933 at 60F. The relationship between the viscosity and gravity indicates the degree of the parafiinic or naphthenic character of the oil.

If a given crude petroleum be distilled into successive fractions and the specific gravities and viscosities of the several fractions determined, it will be found that they conform to the general relationship:

G=a+ log (V -38) in which G is the specific gravity at 60 F., V is Saybolt universal viscosity at 100 F., and a is a constant known as the viscosity-gravity constant. Fractions from each of the different types of crude have different Viscosity-gravity constants. Such constants are lower for fractions of the paraflinic crudes than are the constants for fractions of the naphthenic crudes. An article entitled The Viscosity-gravity constant of petroleum lubrieating oils y J. B. Hill and H. B. Coats,

which will be found in volume 20, page 641 et seq., Industrial'a'nd Engineering Chemistry for June 1928, explains the determination of such constant for several typical oils.

The viscosity-gravity constant is, therefore, an index of the parafii-nicity or naphthenicity of an oil, since when a given crude is distilled and fractions thereof are collected, regardless of the fraction upon which the' specific gravity and the viscosity are taken, when such specific gravity and viscosity are For example, oils 1 '60 ing a viscosity of 400 seconds Sa bolt uni .tives.

' substituted in the formula and the viscosityviscous fractions for some of the typical.

crudes are as follows:

Milltown (Pennsylvania) 0.8067 Burbank (Mid-Continent) 0.8367 Guadalupe (Gulf Coast) 0.8635 Mirando (Gulf Coast) 0.9025

These oils are increasingly parafiinic as the viscosity-gravity constants decrease.

My invention is based upon the discovery that oils containing both the paraflinic series of hydrocarbons and the various naphthenic series may be fractionally extracted with ethylene glycol ethers an their acyl deriva- Ethylene glycol monoalkyl ether, ethylene glycol monoalkyl ether acetate, diethylene glycol monoalkyl ether, and more particularly ethylene glycol monoethyl ether.

nown as cellosolve, ethylene glycol monoethyl ether acetate, known as cellosolve acetate, ethylene glycol monomethyl ether, known as methyl c'ellosolve, and diethylene glycol ,monobutyl ether, known as butyl carbitol, are the selective solvents that I prefer to use, however, other ethylene glycol ethers and their acyl derivatives maybe employed, and are considered within the scope of my invention. The various series of hydrocarbons possess a differential solubility in such solvents; the naphthenic hydrocarbons are much more soluble therein than the paraffinic hydrocarbons. By means of extraction with ethylene glycol ethers and their acyl derivatives, and more particularly with one or more of the specific solvents mentioned above, it is therefore, possible to effect a partial separation of the naphthenic hydrocarbons from theparaflinic, and to obtain'from an oil containing both classes of hydrocarbons, an oil which is much more paraffinic than the original oil and one which is much more naphthenic. By my invention, for example, it is possible to produce an oil of the a quality normally obtained from Appalachian crudes, from crudes of the mixed base type from the Mid-Continent area, and conversely, to obtain oils from mixed base crudes such as are normally obtained from the na hthenic oils of the Gulf Coast area.

' n practicing my invention, I prefer to mix the oil fraction to be treated with a suitable proportion of an ethylene glycol ether or an acyl derivative thereof or a mixture of them, and more particularly with one or more of the specific solvents above mentioned at a temperature sufficiently high so that complete solution is effected and ahomogeneous liquid obtained. I then cool the mixture to a temperature sufliciently low to cause a separation of the liquid into a two-layer system, the upper layer being a solution of a relatively small amount of the solvent in the more parafiinic portion of the oil, and the lower layer prising a solution of the more naphthenic portion of the oil in the solvent. Instead of this'heating and cooling to effect extraction, I may simply agitate the mixture of liquids at normal temperatures. Where substantial qlixlantities of solid hydrocarbons belonging to t e true paraflin series (C H are present, these solids or waxes remain in the upper layer and may cause it to be solid or semisolid. Separation of the two layers is then efiected, for exam le, by decantation, and the solvent removed rom each of the separated oil layers b vacuum distillation or other suitable proce ure, thereby obtainin two oils of similar distillation ranges but 0 widely different physical characteristics and correspondingly different chemical compositions.

Beforeremoving the solvent from the upper and more paraflinic layer of oil obtained in the above described process, I may add a further quantity of solvent, and repeat the bons. While the exact chemical compositions of these compounds are not known, it is probable that the liquid hydrocarbons are branched chain hydrocarbons of the paraffin series, whereas solid bodies are straight chain paraflin hydrocarbons. This product may be further separated into solid and liquid hydrocarbons by any of the well-known dewaxing processes, such as the cold settlin process.

In many instances it will be ound of advantage to'dewax the oil prior; to the extrac-. tion process, as this expedites the manual operation of the latter.

My invention will be further understood from the following specific examples:

100 parts of a previously untreated distillate obtained from a Gulf Coast crude oil and having a viscosity of 612 seconds Saybolt universal at 100 F., aspecifie gravity of 0.9303, and a consequent viscosity gravity constant of 0.874 was mixed with 100 arts of cellosolve acetate and heated to slight y above the temperature of complete miscibility, which in this particular case was 22 C. The

homogeneous liquid which resulted was com- 1 and a viscosit gravity a mg a viscosity versal at 100 and a viscositfy late obtained and vacuum distillation. The cellosolve acetate dissolved fraction yielded 83 arts of cellosolve acetate and 22.3 parts 0 oil having a viscosity oil-170 seconds Saybolt universal at 100 F., a specific gravity of 0.9833 and a viscosity'gravity constant of 0.942. The undissolved fraction ielded 17. arts of cellosolve acetate and 7?.7 parts 0 an oil havin a viscosit of 502 seconds Saybolt universa at 100 and a specific gravity of 0.9159,

constant of 0.858.

a previously untreated distilfrom a Gulf Coast crude oil having a viscosity of 612 secondsSaybolt universal at 100, a specific grav1ty of 0.9303, and a consequent viscosity gravity constant of 0.874 were mixed with 100 parts of cellosolve ,and heated to slight] above the tem rature of complete miscibi it which in t 's particular case was 60 C. T e homogeneous liquid which resulted was cooled with a 'tation to 40 (1., and allowed to settle w ereupon a two layer system formed, which consisted of an upper undissolved oil layer comprising 54.3 parts of the mixture an a lower layer of oil dissolved in cellosolve comprising approximately 345.7 arts of the mixture. After separation, the ayers were each freed from cellosolve by vacuum distillation. The cellosolve dissolved fraction yielded 291 parts of cellosolve and 54.7 parts of oil havof 940 seconds Saybolt uni- F., a specific gravity of 0.9561, gravity constant of 0.906. The undissolved raction yielded 9 parts of cello solve and 45.3 parts of an oil aving a viscosity of 464 seconds Saybolt universal at 100 F., and a specific gravity of 0.9030, and a viscosity gravity constant of 0.842.

100 parts of a *previously untreated distillate obtained from a Gulf Coast crude oil and having a viscosity of 612 seconds Saybolt universal at 100 F., a specific gravity of 0.9303, and a consequent viscosity gravity constant of 0.874 was mixed with 100 parts 00partso of methyl cellosolve and heated to slightly above the tem rature of complete miscibility, which in t is particular case was120 C. The homogeneous liquid which resulted was cooled with agitation to 98 (3., and allowed to settle whereupon a two layer system formed, which consisted of an upper undis- 'solved oil layer comprising 100 parts of the (mixture and a lower layer of oil dissolved in methyl cellosolve comprisin 100 parts of the mixture. fter se aration, the layers were each freed from met yl cellosolve by vacuum distillation. The methyl cellosolve dissolved fraction yielded, 82 parts of methyl cellosolve and 18 parts of oil having "a viscosity of 65.4 seconds Saybolt universal at 210 F., a specific gravity of 0.9738, and a viscosity gravity constant of 0.929. The undissolved fraction yielded 18 parts of -methyl cellosolve and 82 parts of an oil-haw approximately F., and a specific gravity of viscosity gravity constant of untreated I dis- Coast crude oil of 587 second Saybolt unihaving a viscosity of 612 seconds Saylayer comprising 24.5 parts of the mixture and a lower layer of oil dissolved in butyl carbitol comprising ap roximately 375.5 parts of the mixture. A er separation, the ayers were each freed from butyl carbitol by; vacuum distillation. The butyl carbitol dissolved fraction yielded 297 parts of butyl carbitol and 78.5 parts of oil having a viscosity of 701 seconds Saybolt universal at F.-,.a sepecific gravity of 0.9383 and a viscosity gravity constant of 0.884. The undissolved fractlon yielded 3 parts of butyl carbitol and 21.5 parts of an 011 having a viscosity. of 325 seconds Saybolt universal at 100 F., and a s a viscosity gravity constant of 0.830.

From the above examples it will be seen that by one extraction with the solvent there may be obtained oil fractions which are respectively higher in parafiinicity and naphthenicity than the original oil. By repetition of the extraction process upon the undissolved fraction, oils may be obtained which are increasingly parafiinic, as evidenced by progressively decreasing viscosity-gravity constants. I

pecific gravity of 0.8905, and

It is evident that my process is practically independent of the particular nature or source of the crude oil, and that there may be produced thereby oils of desired characteristics from oils which heretofore have not been used as a source of oils of such desired characteristics.

For example, my process may be employed to produce from petroleum of a mixed base type such as would, on normal batch distillation, give a residuum with a viscosity of 150 seconds Saybolt universal at 210 F. with a specific gravity of 0.928 or more, a lubricating stock with a viscosity of 150 seconds Saybolt universal at 210 F., or more, and a specific gravity not higher than 0.910. This latter combination of properties is typical of cylinder stocks produced from Pennsylvania crudes.

In extracting amounts of wax, for example, by

oils containing appreciable such oils may be dewaxed, cold settling or centrifug- Hereinabove, mixtures of solvents havebeenreferred to. It is to be understood that I mg in such mixtures the constituent solvents'will not react with one another, nor with the oil upon which they are to be used, and that such mixtures will contain substantial amounts of an ethylene glycol ether or an acyl derivative thereof. I

For brevity, in the appended claims, the term ethylene glycol ether is employedin a generic sense to include one or a mixture of ethylene glycol ethers and their acyl derivatives, or a mixture of solvents which contains substantial quantities of ethylene glycol ethers and their acyl derivatives,

Also where herein and in the appended claims, an oil is specifically referred to as being viscous, it is to be understood that the oil is of substantial viscosity, i. e., of theorder of 50 seconds Saybolt universal at 100 F., or more.

- What I claim is. 1. In the art of refining mineral oils, the process which comprises separating an oil containing paraflinic and naphthenic hydrocarbonsinto fractions respectively richer in paraflinic and naphthenic compounds by extracting said oil with an ethylene glycol ether. 2. In the art of refining mineral oils, the rocess which comprises fractionally extractan oil containing paraflinic and naphthenic hydrocarbons with anethylene glycol ether to produce fractions of the oil respectively richer in paraflinic and naphthenic compounds.

3. In the art of refining mineral oils, the process which comprises adding an ethylene glycol ether to an oil containing paraflinic and naphthenic hydrocarbons, heating the mixture to such temperature as to effect solution, cooling the solution to form a two layer l system, and separating the upper layer from the lower layer.

4. In the art of refining mineral oils, the process which comprises adding an ethylene glycol ether to an oil'containing paraflinic and naphthenic hydrocarbons, heating the mixture to such temperature as to effect solution, coolingthe solution to form a two layer system, removing'the lower layer, and similarly retreating the upper layer with an ethylene glycol ether.

5. In the art of refining mineral oils, the process which comprises bringing a mineral oil containing parafiinic and naphthenic hydrocarbons into contact with an ethylene glycol ether, thereby to efi'ect solution of a portion richer in naphthenic hydrocarbons in the ethylene glycol ether, separating the solution so formed from the remainder of .the oil, and removing the ethylene glycol ether from both portions of the oil, thereby to obta in fractions of the oil respectively richer.

in paraflinic and naphthenic hydrocarbons.

6. The process for, separating mineral oils containing parafiinic and naphthenic hydrocarbons into fractions which comprises bringin the oil into contact with an ethylene glyc0 ether, thereby to efl'ect solution of a or- I tion of the oil richer in naphthenic hy rocarbons in the ethylene glycol ether, separatspectively richer in parafiinic and naphthenic hydrocarbons.

7. In the art of refining mineral oils, the I process which comprises. bringin a mineral oil containing paraflinic and nap thenic hydrocarbons into contact with an ethylene glycol ether, thereby to effect solutionof a portion richer in naphthenic hydrocarbons in the ethylene glycol ether, separating the solution so formed from the remainder of the oil, and retreating the oil remaining with additional amounts of an ethylene glycol ether.

8. The method of producing paraifinic lubricating oil from mixed base crude which comprises distilling the crude and bringing a portion thereof into contact with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl carbitol, thereby partially dissolving the oil, separating the solvent solution of oil so treated, and removing the solvent from the treated oil.

9. The process of producing a lubricating stock of specific gravity less than .910 and of Saybolt universal viscosity greater than 150 seconds at 210 F. from a crude petroleum which on normal distillation yields a re- 5 siduum of 150 seconds Saybolt universal viscosity at 210 F. and a specific gravity greater than .928, which comprises producing a residuum from the crude petroleum, and

extracting said residuum from said crude v petroleum with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl car bitol.

10. In the art of refining mineral lubricating oil containing paraflinic and naphthenic hydrocarbons, the step of fractionally extracting the oil with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl carbitol, to effect separation of fractions respectively richer in parafiinic and naphthenic compounds.

.11. The process of producing a lubricating stock of specific gravity less than .910 and of Saybolt universal viscosity greater than 150 seconds at 210 F. from a crude petroleum which on normal distillation yields a residuum of 150 seconds Saybolt universal viscosity at 210 F. and a specific gravity greater than .928, which comprises separating a residuum from said crude petroleum and bringing such residuum into contact with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve ace- 7 tate and butyl carbitol, to effect solution of a till portionthereof with the solvent, separating the solvent solution of oil from the portion which does not dissolve therein, and removing the solvent from the oil of said solution.

12. In a process for separating a viscous mineral oil containing paraffinic and naphthenic hydrocarbons into fractions which are respectively richer in naphthenic hydrocarbons and parafinic hydrocarbons other than Wax, the step which comprises extracting the oil with one or more solvents from the group consisting of cellosolve, meth l cellosolve, cellosolve acetate and butyl carbitol.

13. In a process for separating viscous mineral oil liquid at ordinary temperature containing parafinic and naphthenic hydrocarbons into fractions respectively richer in parafinic and naphthenic hydrocarbons, the step which comprises extracting the oil with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl carbitol.

M. In a rocess for separating a substantially wax 'ree viscous mineral oil containing parafinic and naphthenio hydrocarbons into fractions respectively richer in parafinic and comprises extracting the oil with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve'acetate and butyl carbitol. I

15. The process of treating a viscous frac: tion of a crude oil of one type containing parafl'inic and naphthenic hydrocarbons to procure a fraction having the quality of a corresponding fraction of a crude oil of different type having a greater content of parafiinic hydrocarbons, which comprises extracting the viscous fraction with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl carbitol, and separating the oil so treated into portions res ectively richer in paraflinic and naphthenic hydrocarbons.

16. The process of treating a viscous fraction of amixed base crude oil to procure a fraction having the quality of a corresponding fraction of a parafl'mic base crude, which comprises extracting the viscous fraction with one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl carbitol, and separating the oil so treated into portions respectively richer in paraflinic and naphthenic compounds.

17. In the art of refining mineral oils, the process which comprises adding one or more solvents from the group consisting of cellosolve methyl cellosolve, cellosolve acetate and butyl carbitol to a viscous oil liquid at Ol'dlnary tem ratures containing paraflinic and naphthemc hydrocarbons heating the mixture to a temperature suliicient to eflect solution, cooling the solution to a temperature suflicient to form two layers respectively richer in naphthenic hydrocarbons and paraflinic hydrocarbons other than wax, and separating the upper layer richer in parafiinic hydrocarbons from the lower layer richer in naphthenic hydrocarbons.

.18. In the art of refining mineral oils, the process which comprises adding one or more solvents from the group consisting of cellosolve, methyl cellosolve, cellosolve acetate and butyl carbitol to a viscous .oil liquid at ordinary temperatures containing parafiinic and .naphthenic hydrocarbons, heating the mixture to a temperature suficient to effect solution, cooling the solution to a temperature sufficient to form two layers, separating the solvent and parafin wax from the upper layer, and separating the solvent" from the lower layer to produce one fraction richer in parafinic and a second fraction richer in naphthenic hydrocarbons than said viscous oil.

In testimony, whereof I afiix my signature... I

LAWRENCE M. HENDERSON.

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